The invention relates generally to an apparatus for processing food products and, more particularly, to an apparatus for stabilizing the surface of a food product so that further processing of the food product is easily accomplished.
Protein is capable of forming a stable shape by thermal gelation (e.g., cooked eggs), chemically induced coagulation (e.g., tofu), freezing or deep fat frying (e.g., frozen or fried meatballs), or incorporating a hydrocolloid followed by setting with divalent cations (e.g., alginate with calcium ions). When the food material is solid or semi-solid, shape formation can be achieved using special machines, such as a patty machine or a sausage type stuffing machine. With fluid or semi-fluid materials, stabilized forms can be achieved by confining the materials to a mold, container, or package while subjecting the protein-containing material to heating, freezing, or chemical treatment.
Many types of machines are known for producing shaped food products, such as hot dogs, sausages, and meatballs. For example, U.S. Pat. No. 4,379,356, Geissbuhler, discloses an apparatus for making skinless sausages. Tubes are filled with a meat mixture and exposed to a heat source such that the meat is at least partially coagulated. The tubes may be heated by thermal conduction, or microwave heating. Another apparatus for making skinless sausages is shown in U.S. Pat. No. 5,141,762, Mally. Sausage batter is fed into a molding compartment which is surrounded by a heating assembly. Batter passes through the molding compartment and is surface cooked or congealed to form a proteinaceous skin. The batter is then cut into partially shaped products, and further processed. The heating assembly uses thermal conduction to heat the surface of the batter.
Heating oil is used to heat the surface of the apparatus for cooking meatballs shown in U.S. Pat. Nos. 4,073,225, Lang-Ree and 4,103,605, Hemborg et al. Internal heating elements are used to heat the surface of the rollers used to cook the meatballs in U.S. Pat. No. 3,991,665, Lang-Ree et al.
Other methods of processing such food materials include using infrared radiation to stabilize the surface of the food product, as is shown in U.S. Pat. No. 4,729,898, Brule, and U.S. Pat. No. 4,680,183, van Schouwenburg.
However, the use of thermal conduction and infrared radiation for stabilizing the surface of proteinaceous material is not energy efficient.
Some types of proteinaceous materials are difficult to process. For example, vegetable protein materials are particularly difficult to process due to the nature of the protein which does not provide sufficient binding in the raw state and the lack of rendering upon cooking. Typically, deep fat frying is necessary for mass production. However, this makes it difficult to produce a low-fat vegetarian food product.
Therefore, it is an object of the present invention to provide an energy efficient apparatus for stabilizing the surface of proteinaceous food products to allow subsequent handling or processing.
It is a further object of the present invention to provide an apparatus for producing shaped food products with little or no fat in the final product.
These, together with other objects and advantages of the invention will become more readily apparent to those skilled in the art when the following general statements and descriptions are read in the light of the appended drawings.